OFLOPS-Turbo: Testing the next-generation OpenFlow switch

The heterogeneity barrier breakthrough achieved by the OpenFlow protocol is currently paced by the variability in performance semantics among network devices, which reduces the ability of applications to take complete advantage of programmable control. As a result, control applications remain conservative on performance requirements in order to be generalizable and trade performance for explicit state consistency in order to support varying performance behaviours. In this paper we argue that network control must be optimized towards network device capabilities and network managers and application developers must perform informed design decision using accurate switch performance profiles. This becomes highly critical for modern OpenFlow-enabled 10 GbE optical switches which significantly elevate switch performance requirements. We present OFLOPS-Turbo, the integration of the OFLOPS switch evaluation platform, with the OSNT platform, a hardware-accelerated traffic generation and capture system supporting lossless 10 GbE functionality. Using OFLOPS-Turbo, we conduct an evaluation of flow table manipulation capabilities in a representative collection of 10 GbE production OpenFlow switch devices and interpret the evolution of OpenFlow support by comparison with historical data.This work was jointly supported by the EPSRC INTERNET Project EP/H040536/1 and the Defense Advanced Research Projects Agency (DARPA) and the Air Force Research Laboratory (AFRL), under contract FA8750-11- C-0249. The views, opinions, and/or findings contained in this article/presentation are those of the author/ presenter and should not be interpreted as representing the official views or policies, either expressed or implied, of the Defense Advanced Research Projects Agency or the Department of Defense.This is the final version of the article. It first appeared from IEEE via http://dx.doi.org/10.1109/ICC.2015.724921

Private 5G and its Suitability for Industrial Networking

5G was and is still surrounded by many promises and buzzwords, such as the famous 1 ms, real-time, and Ultra-Reliable and Low-Latency Communications (URLLC). This was partly intended to get the attention of vertical industries to become new customers for mobile networks, which shall be deployed in their factories. With the allowance of federal agencies, companies deployed their own private 5G networks to test new use cases enabled by 5G. But what has been missing, apart from all the marketing, is the knowledge of what 5G can really do? Private 5G networks are envisioned to enable new use cases with strict latency requirements, such as robot control. This work has examined in great detail the capabilities of the current 5G Release 15 as private network, and in particular its suitability with regard to time-critical communications. For that, a testbed was designed to measure One-Way Delays (OWDs) and Round-Trip Times (RTTs) with high accuracy. The measurements were conducted in 5G Non-Standalone (NSA) and Standalone (SA) net-works and are the first published results. The evaluation revealed results that were not obvious or identified by previous work. For example, a strong impact of the packet rate on the resulting OWD and RTT was found. It was also found that typically 95% of the SA downlink end-to-end packet delays are in the range of 4 ms to 10 ms, indicating a fairly wide spread of packet delays, with the Inter-Packet Delay Variation (IPDV) between consecutive packets distributed in the millisecond range. Surprisingly, it also seems to matter for the RTT from which direction, i.e. Downlink (DL) or Uplink (UL), a round-trip communication was initiated. Another important factor plays especially the Inter-Arrival Time (IAT) of packets on the RTT distribution. These examples from the results found demonstrate the need to critically examine 5G and any successors in terms of their real-time capabilities. In addition to the end-to-end OWD and RTT, the delays caused by 4G and 5G Core processing has been investigated as well. Current state-of-the-art 4G and 5G Core implementations exhibit long-tailed delay distributions. To overcome such limitations, modern packet processing have been evaluated in terms of their respective tail-latency. The hardware-based solution was able to process packets with deterministic delay, but the software-based solutions also achieved soft real-time results. These results allow the selection of the right technology for use cases depending on their tail-latency requirements. In summary, many insights into the suitability of 5G for time-critical communications were gained from the study of the current 5G Release 15. The measurement framework, analysis methods, and results will inform the further development and refinement of private 5G campus networks for industrial use cases

SDN as Active Measurement Infrastructure

Active measurements are integral to the operation and management of networks, and invaluable to supporting empirical network research. Unfortunately, it is often cost-prohibitive and logistically difficult to widely deploy measurement nodes, especially in the core. In this work, we consider the feasibility of tightly integrating measurement within the infrastructure by using Software Defined Networks (SDNs). We introduce "SDN as Active Measurement Infrastructure" (SAAMI) to enable measurements to originate from any location where SDN is deployed, removing the need for dedicated measurement nodes and increasing vantage point diversity. We implement ping and traceroute using SAAMI, as well as a proof-of-concept custom measurement protocol to demonstrate the power and ease of SAAMI's open framework. Via a large-scale measurement campaign using SDN switches as vantage points, we show that SAAMI is accurate, scalable, and extensible

An integrated SDN-based architecture for Passive Optical Networks

Passive Optical Network (PON) are often managed by non-flexible, proprietary network management systems. Software Defined Networking (SDN) opens the way for a more efficient operation and management of networks. We describe a new SDN-based architecture for Ethernet Passive Optical Networks (EPON), in which some functions of the Optical Line Terminal (OLT) are virtualized and located in an external controller, while keeping the rest of the PON functionality around an Open Flow switch. This opens the way for an improved management of the resource usage, bandwidth allocation, Quality-of-Service (QoS) monitoring and enforcement, or power consumption management, among other possibilities. In order to maintain the time-sensitive nature of the EPON operations, synchronous ports are added to the switch. OpenFlow messages are extended in order to cope with the PON-related parameters. Results based on simulations demonstrate that our proposal performs similarly or better than legacy architectures, in terms of delay and throughput.Postprint (author's final draft

Uncertainty-driven Ensemble Forecasting of QoS in Software Defined Networks

Software Defined Networking (SDN) is the key technology for combining networking and Cloud solutions to provide novel applications. SDN offers a number of advantages as the existing resources can be virtualized and orchestrated to provide new services to the end users. Such a technology should be accompanied by powerful mechanisms that ensure the end-to-end quality of service at high levels, thus, enabling support for complex applications that satisfy end users needs. In this paper, we propose an intelligent mechanism that agglomerates the benefits of SDNs with real-time “Big Data” forecasting analytics. The proposed mechanism, as part of the SDN controller, supports predictive intelligence by monitoring a set of network performance parameters, forecasting their future values, and deriving indications on potential service quality violations. By treating the performance measurements as time-series, our mechanism employs a novel ensemble forecasting methodology to estimate their future values. Such predictions are fed to a Type-2 Fuzzy Logic system to deliver, in real-time, decisions related to service quality violations. Such decisions proactively assist the SDN controller for providing the best possible orchestration of the virtualized resources. We evaluate the proposed mechanism w.r.t. precision and recall metrics over synthetic data

A proposal for an SDN-based SIEPON architecture

Passive Optical Network (PON) elements such as Optical Line Terminal (OLT) and Optical Network Units (ONUs) are currently managed by inflexible legacy network management systems. Software-Defined Networking (SDN) is a new networking paradigm that improves the operation and management of networks. In this paper, we propose a novel architecture, based on the SDN concept, for Ethernet Passive Optical Networks (EPON) that includes the Service Interoperability standard (SIEPON). In our proposal, the OLT is partially virtualized and some of its functionalities are allocated to the core network management system, while the OLT itself is replaced by an OpenFlow (OF) switch. A new MultiPoint MAC Control (MPMC) sublayer extension based on the OpenFlow protocol is presented. This would allow the SDN controller to manage and enhance the resource utilization, flow monitoring, bandwidth assignment, quality-of-service (QoS) guarantees, and energy management of the optical network access, to name a few possibilities. The OpenFlow switch is extended with synchronous ports to retain the time-critical nature of the EPON network. OpenFlow messages are also extended with new functionalities to implement the concept of EPON Service Paths (ESPs). Our simulation-based results demonstrate the effectiveness of the new architecture, while retaining a similar (or improved) performance in terms of delay and throughput when compared to legacy PONs.Peer ReviewedPostprint (author's final draft